Carton and latch construction

ABSTRACT

There is disclosed an egg carton or similar article made of foamed polystyrene or like material comprising a top portion and a bottom portion hinged along one side and releasably fastened along the other side and/or ends by one or more latching means. The bottom portion of the carton having the egg cells is molded such that a plurality of vertical protrusions are formed along its edge, each protrusion having an outwardly projecting hook at its upper end. These hooks lock into catches or detents molded into the wall of the top portion. The latching means do not extend beyond the edges of the carton and thus do not increase its width or length. Further means are provided to resist opening when the cartons are stacked.

United States Patent [7 2] lnventors Roderick F. McKenna Hyannisport;Robert McCormick, Barnstable; Howard A. Rohdin, Waquoit, Mass.; DonTucker, Southport, Conn.

[21] Appl. No. 789,856

[ 22] Filed Jan. 8, '1 969 [45] Patented Mar. 16, 1971 [73] AssigneePackaging Industries, Inc.

' Hyannis, Mass.

[54] CARTON AND LATCH CONSTRUCTION 6 Claims, 9 Drawing Figs.

[5 2] US. Cl. H 229/44, 229/2.5 [51] Int. Cl 865d 45/00 [50] Field ofSearch 224/44, 45, 2.5

[56] References Cited UNITED STATES PATENTS 2,591,446 4/1952 Lemmon229/25 3,245,600 4/ l 966 Friday 229/25 3,258,186 6/1966 Greatman...229/25 3,258,187 6/1966 Greatman... 229/25 3,396,895 8/1968 Pearl et al.229/25 3,471,078 10/1969 Seest et al 229/44 Primary Examiner-Davis T.Moorhead Attorney-Brumbaugh, Graves, Donohue & Raymond ABSTRACT: Thereis disclosed an egg carton or similar article made of foamed polystyreneor like material comprising a top portion and a bottom portion hingedalong one side and releasably fastened along the other side and/or endsby one or more latching means. The bottom portion of the carton havingthe egg cells is molded such that a plurality of vertical protrusionsare formed along its edge, each protrusion having an outwardlyprojecting hook at its upper end. These hooks lock into catches ordetents molded into the wall of the top portion. The latching means donot extend beyond the edges of the carton and thus do not increase itswidth or length. Further means are provided to resist opening when thecartons are stacked.

PATENTEUHARI 619?! 34570747 sum 1 0F 4 NNNNNNNN S RQDERI IF. M KENNAROBER CCORMICK HOWARD A. ROHDIN 5y DON TUCKER PATENTED MAR 1 6 Ian SHEET2 OF 4 INVENTORS:

RODERICK F. McKENNA ROBERT McCORMICK HOWARD A. ROHDIN DON TUCKER M244,W,

PATENTEU m1 6 IQYI sum 3 OF 4 FIE. 4?,

INVENTORS:

RODERICK F McKENNA ROBERT McCORMlCK HOWARD A. ROHDl-N B DON TUCKER WAMKM PATENTED MARI 6 I97! SHEEY 8 0F 4 INVENTORS:

RODERICK FMcKENNA ROBERT McCORMlCK HOWARD A. ROHDIN DON TUCKER CARTONAND LATCH CONSTRUCTION BACKGROUND OF THE INVENTION Many forms of eggcartons presently in use rely on flaps, tabs, and similar expedients tokeep them closed. Some of such closure means include protrusions atvarious points along the edges of the cartons, and the overalldimensions of the cartons are thereby increased. This prevents thecartons from being readily stacked in accordance with standard sizepackaging requirements, decreases the stability of the carton stacks,and increases the amount and cost of the raw material from which thecartons are manufactured.

Other presently known closure means for egg cartons depend upon theprovision of additional flaps which add to the cost of materials and thecomplexity of production.

A recent innovation in the manufacture of egg cartons is the use offoamed polystyrene in sheet form as the material for the carton. Thesheet, of uniform thickness, is thermoformed, i.e., pressed under heat,between mating dies to the desired shape. The ready compressibility andelasticity of the this material when warm enables complex shapes withlarge surface area to be formed from a blank having less surface area.One form of carton that may be produced from foamed polystyrene isdescribed in copending application Ser. No. 743,673, filed Jul. 10,1968, for Protective Container and Method of Sealing and OpeningThereof, in the names of Bambara and Rohdin, and assigned to the presentassignee.

It is the primary object of the present invention to provide an improvedegg carton construction that avoids the shortcomings of existingcartons.

Another object of this invention is to provide an improved latchingmeans for an egg carton, which latching means does not protrude beyondthe sides of the package and requires no extra material for itsformation.

It is a further object of this invention to provide such an egg cartonthat will resist opening when twisted during racking.

Still another object of this invention is to provide such an improvedegg carton that lends itself to ready production on conventionalmachinery.

BRIEF SUMMARY OF THE INVENTION In accordance with the invention, thecarton blanks are thermoformed of foamed polystyrene with the cartonbottom having the egg cells formed with a plurality of raised sisemicylindrical portions extending perpendicularly outward of the edgebetween pairs of cells. When the blank is trimmed, each of thesemicylindrical portions are cut vertically inside of the finished edgeof the carton to form one-half of the latch means. Mating latch partsare molded along the edges of the top of the carton so that when foldedshut, the latch parts, all of which are inside of the finished edges ofthe carton, firmly hook together. The latch means may be located alongthe iongitudinal edge of the carton or at its ends or both.

To resist opening when racked, elongated depressions in the cartontopare formed which, when the carton is closed, will bear against the topsof the posts between clusters of the egg cells. This gives addedrigidity to the carton. If desired, the carton may be heat staked orsealed after filling at the contacting portions along the edges betweenadjacent egg cells where no latches are formed.

The resultant construction provides a firm, strong egg carton that maybe securely closed without bulky latching means requiring added materialor extending. beyond the edges of the carton. It may be readily anduniformly stacked and resists opening when twisted during handling. Theimproved latch means, by requiring no openings to be made in the carton,does not weaken the carton and thereby extends its life.

BRIEF DESCRIPTION OF THE DRAWINGS For a better understanding of theinvention, reference may be made to the following detailed descriptionand to the drawings, in which:

FIG. 1 is a perspective view of the egg carton of the inven- I tion in apartially open position;

FIG. 2 is a perspective view-of the egg carton of FIG. 1 in the fullyopen position;

FIG. 3 is a transverse section through the latch means of the carton inclosed position;

FIG. is a section similar to that of FIG. 3 with the carton partiallyopen, and showing in dotted lines the relationship of an adjacent bottomportion as formed on the blank;

FIG. 5 is a partial elevation of the bottom part of the latch meanstaken from the direction indicated by the arrows 5-5 of FIG. 4;

FIG. 6 is a partial plari view of the closed carton;

FIG. 7 is an elevation of the closed carton showing the latch means inclosed position;

FIG. 8 is a partial longitudinal section through a closed cartonillustrating another form of antiracking means; and

FIG. 9 is a broken top view of a carton showing latching means at theends and along one side.

DETAILED S DESCRIPTION OF THE INVENTION Referring now to FIGS. 1 and 2,an egg carton ll embodying the invention consists of a top portion 12and a bottom portion 13 both of generally rectangular shape.

The carton preferably is made of a plastic substance, such as foamedpolystyrene, which can be thermoformed. However, an any suitablemoldable material may be used. Sheet material that can be mechanicallyfolded or cut is also suitable and the carton can be manufactured onmachinery of the type currently used in the industry.

The bottom portion 13 contains a series of egg receiving cells I4,shaped and dimensioned to accommodate eggs of any of the standard sizes,with vertical projections or posts 30 formed between each cluster ofcells. The top portion or lid 12 has a generally flat upper wall 15,sloping sidewalls l6, and sloping end walls 17. The dimensions of thetop portion are such that when the carton is closed and latched, theeggs in the carton are snugly held in the cells.

The top and bottom portions are hinged together along correspondinglongitudinal edges 18. The hinge may be continuous formed by crimpingalong a line separating the two portions of the carton which arethermoformed from a single sheet of plastic material, or it may bediscontinuous, The latter, as shown in the above-mentioned copendingapplica' tion, may be obtained by making a series of short cuts alongthe crimped common edge.

The remaining longitudinal and transverse edges of the car ton portionsmeet,such as seen in FIG. 6 and 7, to define with the hinged edge, themaximum exterior dimensions of the carton, which are generallyrectangular. As will be described hereinafter, no portion of the carton,including the latch means, extends beyond the edges of the cartons,enabling uniform stacking without difficulty.

The lath latch means 21, the three of which are shown in the embodimentof FIGS. 1 and 2, are formed in the top and bottom portions of thecarton, adjacent to but interiorly of the mating edges 24, 28 so thatthey do not extend beyond the carton when closed. As seen best in FIGS.1 and 2, they are positioned between pairs of cells 14 where sufficientmaterial is available to form them without increasing the size of theblank. Openings 26 along the transverse edgesof the cartons may beprovided to permit air circulation and to allow limited viewing of thecontents.

Each latch meansZl comprises a hook 22 and an inwardly extending bulgeor detent 23 which engage one another. The hook is molded in the bottomportion of the carton and constitutes the horizontally extending uppersegment of a vertical protrusion 25 extending perpendicularly from theedge 24. As seen from FIG. -l, when thennoforrned, a pair of bottomportions are integrally joined edge-to-edge and the protrusion 25extends horizontally between the respective bottom portions. When cut toseparate the individual cartons, the protrusions are severed interiorlyof the final edge 24, and the book therefore does not extend beyond theedge of the closed carton.

The detent 23 in the top portion is molded into the sloping wall 16 atlocations aligned with the hooks 22 in the bottom portion. The detent isin the form of a rounded bulge extending inwardly of an expanded portion27 of the sidewall 16. The lateral dimension of the detent 23 is such asto fit readily between the sides of the protrusion 25 beneath the hook22.

As the carton is closed, the detent 23 slides overt over the top ofprotrusion 25 and into engagement with the hook 22. When all of thelatch means on the carton are so engaged, it is securely closed.However, the resiliency of the material also allows it to be readilyreopened by grasping the top and bottom portions and pulling apart. Theindentations 29 formed along the wall 16 to correspond to theseparations between the egg cells aid in gripping the lid.

As will be apparent, there are no flaps, tabs, or other protrusionsextending beyond the edges of the closed carton. This makes possibleproper carton stacking and results in a reduction in the quantity offoamed material m needed for carton manufacture.

Although latch means 21 have been in the embodiment of FIGS. 1 and 2 asbeing located along longitudinal edge, they may be otherwise positioned.In addition to the longitudinal edge, latch means may be formed at eachtransverse edge of the carton, such as shown in FIG. 9. The hinge 18 mayalso be replaced by one or more latch means to allow the lid 12 to becompletely removed, if desired.

As noted above, vertical posts 30 are located in the bottom portion ofthe carton approximately along its longitudinal center line and betweenclusters of adjacent egg-receiving cells 14. These posts, in conjunctionwith elongated ribs 31 formed in the cover piece of the top portion 12along its longitudinal center line, serve to increase the strength andrigidity of the closed carton, thereby to better protect its contents,and also act to resist opening when twisting forces are applied duringracking. When the egg carton is closed, as in FIG. 3, the ribs 31contact the posts 30. Thus any weight imposed upon the top portion willbe supported by the posts and not by the contents of the carton. Therigidity provided by this structure also serves to resist the twistingforces which tend to open the cartons during racking.

FIG. 8 illustrates an alternate embodiment of such structure. Here, adepression 32 is formed in the top of each post 38 and each rib has aplurality of downwardly extending pips 33 which fit into thedepressions. Here then, the posts 30 not only support but alsopositively engage the elongated ribs of the top portion. Thisarrangement provides more resistance to racking forces which tend totwist the top and bottom portions of the carton apart.

It will be seen that the above-described carton may be readily made withconventional thermoforming machinery. If desired to protect the contentsafter filling, the carton sections may be heat staked or sealed togetheralong the mating edges 24, 28, as indicated at 36 in FIGS. 6 and 7. Thiswill resist casual or accidental opening of the cartons and willindicate to the purchaser, if opened, that a carton or its contents mayhave been tampered with. The purchaser will of course, be able to openthe or sealed carton by pulling apart without interfering with continuedfunctioning of the latch means.

It will be understood that many variations and modifications of theillustrated embodiments may be made by one skilled in the art withoutdeparting from the spirit and scope of the invention. All suchvariations and modifications, therefore, are intended to be includedwithin the scope of the appended claims.

We claim:

l. A carton for containment of eggs comprising a bottom portion formedwith a plurality of egg-receiving cells and vertically extending postsbetween adjacent cells, a top portion having sidewalls and formed to fitover and contain eggs placed in said egg cells, said bottom and topportions meeting when closed in respective pairs of common outer edges,said common edges meeting in a common horizontal plane and definin theouter dimensions of the carton in said plane, latch means or ereleasably securing the top and bottom portions together along one pairof common outer edges, said latch means comprising a hollow verticalprotrusion formed in said bottom portion inside said common edgethereof, said protrusion being located between a pair of adjacent eggcells and comprising generally vertical extensions of the walls of saidadjacent egg cells merging into a joint portion at their upper ends,said wall extensions and said joint portion terminating in a commonvertical plane disposed inwardly of said common outer edge and exposingthe hollow interior of said protrusion, the joint portion therebyproviding a hook extending outwardly towards and terminating terminatinginteriorly of the edge of the carton, and a catch for engaging saidhook, said catch being formed in said top portion adjacent thecorresponding common outer edge thereof, and comprising and inwardlyextending bulge formed in a sidewall of said top portion, no part ofsaid sidewall extending beyond the outer edge of said top portion, saidsidewall, including latch means, having no apertures therein, and meansfor securing the top and bottom portions together along a pair of commonedges opposite to said common edges adjacent said latch means.

2. The carton of claim 1 wherein said carton and latch means areintegrally formed of a foamed plastic material.

3. The carton of claim 2 wherein said foamed plastic material is foamedpolystyrene.

4. A carton according to claim 1 wherein each of said posts betweenadjacent egg cells includes a depression formed in its uppermostsurface, and said top portion includes an elongated, downwardlyextending rih, said rib being provided with projections adapted to besnugly received in the depressions in said posts.

5. A carton as described in claim 1 wherein said means for securing thetop and bottom portions together along a pair of common outer edgesopposite to said common outer edges adjacent said latch means compriseshinge means.

6. A carton as described claim 1 of generally rectangular shape whereinsaid top and bottom portions meet and provide four pairs of common outeredges, and wherein said latch means are provided adjacent more than oneof said pairs of edges.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,510,747 Dated March 16, 1971 Inventor(s) Roderick F. McKenna et a1.

It is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below:

Column 1, line 20, delete "the" second occurrence; line "Jul. should be--July; line 45, delete "si" Colum line 19, after "DETAILED" delete -S;line 26, delete "an"; line 48, "FIG. should be -FIGS.-; line 54 del"lath"; line 54 delete "the" second occurrence. Colum line 7, delete"overt"; line 18 delete "m" after "mate line 20, after "been" insert-shown--; line 57, after insert staked-. Column 4, line 15 after"common" i -outer--; line 17, after "for" delete "e"; line 28, de"terminating" second occurrence.

Signed and sealed this 2nd day of November 1971.

(SEAL) Attest:

ROBERT GOTTSCHALK ARD M.FLETCHER JR. Em Acting Commissioner of PatAttesting Officer

1. A carton for containment of eggs comprising a bottom portion formedwith a plurality of egg-receiving cells and vertically extending postsbetween adjacent cells, a top portion having sidewalls and formed to fitover and contain eggs placed in said egg cells, said bottom and topportions meeting when closed in respective pairs of common outer edges,said common edges meeting in a common horizontal plane and defining theouter dimensions of the carton in said plane, latch means for ereleasably securing the top and bottom portions together along one pairof common outer edges, said latch means comprising a hollow verticalprotrusion formed in said bottom portion inside said common edgethereof, said protrusion being located between a pair of adjacent eggcells and comprising generally vertical extensions of the walls of saidadjacent egg cells merging into a joint portion at their upper ends,said wall extensions and said joint portion terminating in a commonvertical plane disposed inwardly of said common outer edge and exposingthe hollow interior of said protrusion, the joint portion therebyproviding a hook extending outwardly towards and terminating terminatinginteriorly of the edge of the carton, and a catch for engaging saidhook, said catch being formed in said top portion adjacent thecorresponding common outer edge thereof, and comprising and inwardlyextending bulge formed in a sidewall of said top portion, no part ofsaid sidewall extending beyond the outer edge of said top portion, saidsidewall, including latch means, having no apertures therein, and meansfor securing the top and bottom portions together along a pair of commonedges opposite to said common edges adjacent said latch means.
 2. Thecarton of claim 1 wherein said carton and latch means are integrallyformed of a foamed plastic material.
 3. The carton of claim 2 whereinsaid foamed plastic material is foamed polystyrene.
 4. A cartonaccording to claim 1 wherein each of said posts between adjacent eggcells includes a depression formed in its uppermost surface, and saidtop portion includes an elongated, downwardly extending rib, said ribbeing provided with projections adapted to be snugly received in thedepressions in said posts.
 5. A carton as described in claim 1 whereinsaid means for securing the top and bottom portions together along apair of common outer edges opposite to said common outer edges adjacentsaid latch means comprises hinge means.
 6. A carton as described claim 1of generally rectangular shape wherein said top and bottom portions meetand provide four pairs of common outer edges, and wherein said latchmeans are provided adjacent more than one of said pairs of edges.